It seems that both Ronaldo and Bale will start the match, but that will not be confirmed until one hour before the game starts, so the fans have a good reason for being nervous. It all seems much more simple for Bayern though. Real Madrid have enough quality to harm the German side, but Cristiano and Bale are so valuable that their presence in the starting XI is crucial.
Real Madrid: Casillas, Carvajal, Pepe, Ramos, Coentrao, Alonso, Modric, Di Maria, Bale, Ronaldo, Benzema.
Bayern: Neuer, Rafinha, Dante, Boateng, Alaba, Martinez, Lahm, Schwensteiger, Robben, Ribery, Mandzukic.
So Real Madrid will likely keep Isco on the bench while Guardiola will have Kroos, Gotze and Muller waiting. That quality off the bench could make the difference. Expect Real Madrid to play with intensity and Bayern trying to control the game with the possession. If Real Madrid are patient enough, they will create at least a couple of good scoring chances.